iio: Add ABI documentation for RGBC intensity hardware gain factor

This patch adds documentation for RGBC in_intensity_*_hardwaregain.
There is at least one user for these, ADJD-S311-CR999 digital color sensor
driver.

Signed-off-by: Roberta Dobrescu <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>
diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index d9dd70f..ea7e7ab 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -337,6 +337,10 @@
 		are listed in this attribute.
 
 What		/sys/bus/iio/devices/iio:deviceX/out_voltageY_hardwaregain
+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_red_hardwaregain
+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_green_hardwaregain
+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_blue_hardwaregain
+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_clear_hardwaregain
 KernelVersion:	2.6.35
 Contact:	[email protected]
 Description: